1. Field of the Invention
The present invention relates generally to the external fixation of bones. More particularly, the present invention relates to a method and apparatus for external fixation of the pelvis. While not limited thereto, the present invention specifically relates to an apparatus for external pelvic fixation which is applied anteriorly and provides enhanced surgical access to the abdominal area.
2. Discussion of the Related Art
In various orthopedic surgical procedures, it is necessary to secure two bone portions in a relatively fixed relationship to each other. For example, the need for establishing such a secured relationship is often a result of a fracture which has occurred to the bone. To ensure that the bone can regenerate in the proper orientation and fuse the fracture, it is important that the bone portions be accurately aligned and the relative positions maintained for an extended time period.
Various external fixation devices for the repair of traumatized bone are known. For example, commonly assigned U.S. Pat. No. 5,662,650 to Bailey et al. discloses an apparatus for the external fixation of large bones. The apparatus is illustrated to generally include a main body as well as a first and second bone screw clamps. The main body serves to allow the apparatus to axially rotate, thereby providing a proper longitudinal rotational location of the bone screws with respect to a bone. The first bone screw clamp is used to secure a first bone screw to the apparatus while permitting the first bone screw to be axially displaced from the main body. In a similar fashion, the second bone screw clamp functions to secure a second bone screw to the apparatus and to allow the second bone screw to be axially displaced with respect to the main body. U.S. Pat. No. 5,662,650 is incorporated by reference as if fully set forth herein.
In certain orthopedic surgical procedures, it is necessary to externally fixate portions of the pelvis relative to each other. The need for such external fixation is typically the result of a fracture. The pelvis normally functions to support a number of organs in a compact area. When the pelvis fractures (e.g. posterior disruption or anterior disruption), the patient's life may depend on quick closure and stabilization of the pelvis. Other injuries requiring surgical repair may be present due to the nature of the typical accidents resulting in pelvic fractures.
One known device available for pelvic external fixation is shown and described in U.S. Pat. No. 5,350,378. The device includes a frame, first and second fixation bone screws connected to the frame in spaced relationship to each other, an adjustment mechanism for moving the first and second fixation bone screws relative to each other, and an adjustable spacer for adjusting distance between the device and the patient. The disclosed device is specifically intended to be engaged with the pelvis in an posterior fashion.
While known external fixation devices specifically designed for the pelvis, including but not limited to the type disclosed in U.S. Pat. No. 5,350,378, may have proven acceptable for certain applications, such fixators are nevertheless susceptible to improvements that may enhance their performance. For example, many known devices for external fixation of the pelvis must be applied in a posterior fashion (i.e., with a frame passing behind the patient.) Posterior application forces the patient to lie on his or her stomach resulting in additional patient discomfort. In addition, posterior application impedes medical access to the patient's abdomen. Fractures of the pelvis often occur from traffic accidents, free falls, and industrial accidents associated with other severe injuries, often to the abdominal area. Insofar as the present invention is concerned, known devices adapted for anterior application do not provide sufficient surgical access to the patient, particularly in the abdominal area. Furthermore, known devices do not permit independent pin placement allowing for quick installation of pins into the iliac crest.